The spatial arrangement of molecules plays a crucial role in determining the macroscopic properties of functional materials. Coordinated polymers (CPs) formed by self‐assembly of organic isomeric ligands and metals offer unique performance characteristics. In this study, we present the investigation of a one‐dimensional CP, named CIT‐E, composed of tetraphenylethene pyridine derivative (TPE‐2by‐2‐E) ligands and cuprous iodide. The resulting CP exhibits a one‐dimensional bead chain structure with exceptional thermal and chemical stability. By leveraging the competitive absorption between CIT‐E and the explosive analog 2,4‐dinitroaniline, we achieve detection of the explosive through changes in the absorption intensity of the excitation light source and subsequent fluorescence response. The CP demonstrates high selectivity and anti‐interference ability in detecting 2,4‐dinitroaniline in aqueous solution, with a detection linear range of 0.1 μM to 300 μM and a detection limit of 0.05 μM, surpassing the national third‐level emission standard. These findings highlight the potential of CP CIT‐E as a promising material for the detection of explosive nitroaromatic compounds.